There is little existing information about the impact of living alone on health outcomes and survival of the elderly, although the trend continues in the us for the elderly to live alone after becoming widowed. This research will examine the impact of living arrangements and changes in living arrangements on survival over a 16-20 year period among a sample of 7955 US adults aged 45-74 at baseline; will examine the role of diet, demographic and socioeconomic factors, health status, health behaviors, social support, and psychological well-being in the relationship between living arrangements and survival. Data are from the National Health and Nutrition Examination Survey I (NHANES I), 1971-1975, and the three cycles of the NHANES I epidemiologic Followup Study (NHEFS), 1982-1984, 1986 and 1987, as well as mortality data through 1991. The five specific aims are to examine: 1) whether there are differences in the effects of living arrangements on subsequent survival by age and sex; 2) the pattern of changes in living arrangements between baseline and followup; 3; the effects of changes in living arrangements on diet, economic, status, health behaviors, social support, and psychological well-being; 4) whether there are differences in the effects of changes in living arrangements between the four surveys on survival by age, sex, and time since change; and, 5) the role of diet, socioeconomic characteristics, health status, health behaviors, social support, and psychological well-being in accounting for the association between living arrangements and survival; between changes in living arrangements and survival. Proportional hazards regression and multiple logistic regression will be used to test 12 major hypotheses. Exploratory analysis will focus on predictors of survival to age 80 years and older. These surveys are the only nationwide longitudinal data that include information on living arrangements, nutrition, health behaviors, clinical and self-reported health status, and mortality data in the same survey. The findings will have important implications for social policy and intervention programs for improving the quality of life of the large proportion of the elderly who live alone, and for understanding which subgroups are particularly in need of intervention in order to improve survival.